Separable connector clamp



Margth 10, 1959 R. w. BONNET ETAL 2,877,443

SEPARABLE CONNECTOR CLAMP Filed Jan. 1a, 1954 INVENTORS. W WfidmefSEPARABLE CONNECTOR CLAMP Robert W. Bonnet and Thomas G. Connor,Lafayette,

Ind., assignors, by mesne assignments, to Duncan Electric Company,llnc., Lafayette, Ind., a corporation of Indiana Application January 18,1954, Serial No. 404,617

6 Claims. (Cl. 339-272) There are many instances in the electricalindustry in which connecting clamps are desirable for connecting twoconductors. Sometimes the conductors are of such nature that the end ofone may be slipped into the connecting clamp end first. I The connectingclamp of the present invention, however, is especially suitable when theconductor cannot be inserted in that manner. For

example, the conductor may have no end conveniently located. This mightbe the case, for example, when a service conductor supplies current toseveral meters, and a connection is to be made to this conductor in eachof the meter cases through which it passes. Also, a conductor might betoo stiff to be thrust into a connector end first where the spacelimitations are such that the conductor would have to be bent rathersharply for this purpose. In many such instances, it is desirable tohave a separable connector, so that a part of the connector can beremoved and the conductor can then be laid into the connector. For manypurposes, it is desired that the connector be in the form of a clamp, sothat the conductor can be firmly clamped when the connector istightened. There have in the past been many forms of separable connectorclamps in existence or proposed. Compared to those of the past, theconnector clamps made in accordance with the present invention combineto an unusual degree simplicity of assembly, dependability of highpressure clamping, and economy of manufacture.

Additional objects and advantages will be apparent from the followingdescription and from the drawings.

Designation of figures Fig. 1 is a perspective view showing the form ofinvention chosen for illustration, clamping an intermediate point of amovable conductor to a terminal conductor to which the connector clampis secured.

Fig. 2 is a vertical sectional view taken approximately on the line 22of Fig. 1.

Fig. 3 is a perspective view of the removable part of the connectorclamp.

Fig. 4 is a top view of the structure shown in Fig. 3.

Fig. 5 is a view similar to Fig. 2, but showing the structure of Fig. 3being inserted toward the position in which it is seen in Fig. 2, thesides of the main body being sprung apart by the art of insertion.

General description Although the law requires a full and exactdescription of at least one form of the invention, such as that whichfollows, it is, of course, one purpose of a patent to cover each newinventive concept therein no matter how it may later be disguised byvariations in form or additions of further improvements; and theappended claims are intended to accomplish this purpose by particularlypointing out the parts, improvements, or combinations in which theinventive concepts are found.

The connector clamp of the present invention has been illustrated asincluding a U-shaped main body 11, a clamp screw 12 threaded through across piece or cap United States Patent 13 and carrying a clamp plate 14swiveled at the bottom of the screw 12. A terminal 16 has been shownriveted to the base 17 of the main body 11. A conductor 18 has beenshown extending through the connector clamp and clamped by it againstthe terminal conductor 16. The conductor 18 has been illustrated as amultiplestrand conductor which is normally round in overall crosssection, but the pressure of the clamp flattens out the clamped portionof the conductor so that the strands assume such a position asillustrated in Fig. 2.

separability features By unscrewing the screw 12 to the position shownin Fig. 5, and by using a screw driver to spread apart the two legs 21of the U-shaped main body, the cross piece 13 and the parts carried byit may be removed. To reinsert these parts, it is not even necessary touse a screw driver. One of the ears 22 may be slipped into a slot 23 inone of the legs 21 by tilting the cross piece 13. As the cross piece isthen pressed down toward its final position, it passes through theposition shown in Fig. 5, at which position it is spreading the two legs21 apart. It will be understood that the main body 11 is of asuitableresilient material, preferably phosphor bronze. As the crosspiece 13 is pressed a little further, the other car 22 will spring intoits slot 23.

Sturdiness features In spite of the fact that the main body 11 is madeof resilient material and is thin enough to be flexed by manual pressureapplied to the cross piece 22 or to the screw 12, it is highly desirableto have extremely dependable sturdiness, so that there will be nouncertainty in being able to attain a high clamping pressure on theconductor 18.

One of the important considerations is that the two legs 21 must bedependably locked so that they will not spring out under the influenceof upward pressure on the cross piece 13 as the screw 12 is screweddown. The simplest and most desirable method of accomplishing thisinterlock has been found to be merely a matter of shaping the cars 22 sothat their upper surfaces slope inwardly and downwardly as clearly seenin Fig. 2. Even with the legs 21 thus firmly locked against spreading,there remains the problem of being sure that the cross piece 13 will nottear loose by tearing or excessively deforming the metal of the sides orlegs, 21 above the slots 23. It has been found possible to accomplishthis by the cooperation of several features:

One of the most important features is that the metal of legs 21 beyondthe slots 23 lie in the plane which most effectively resists the pull ofthe ears 22 on this metal. Accordingly, it will be seen from Fig. 2 thata substantial length of metal above the slots 23 is, on each leg 21, inthe plane perpendicular to the base 17, or in other words in the planeof the direction of the pull on ears 22. Beyond the area in question,the legs 21 are flared outwardly as at 24, so as to facilitate theinsertion of the cross piece.

It is also important that the ears 22 avoid bearing on the legs 21 atthe corners of the slots 23. To this end it is desirable that the ears22 be relieved somewhat in the vicinity of these corners. Accordingly tothe preferred form of the present invention, this is accomplished bycrowning the cars 22, so that they are higher at their center area thanat the sides, and hence the upper face slopes to the full extent only inthe central area. It has been found practical and economical to shapethe cross piece 13 to the desired shape by a coining operation.Preferably it is made of cold rolled steel. The coining preferablyleaves the corners of the ears unaltered.

A further feature contributing toward the necessary 3 sturdiness is toavoid a sharp corner at the upper corners of the slots 23. In fact, allfour corners of the slots are preferably provided with a slight radius,a radius of ,6 inch having been found adequate.

Another dimension which may be mentioned as ha. ing been foundsatisfactory is the height of the fiat part of legs 21 above slots 23. Aheight of .075 inch has been found to be sufficient where the materialthickness was .050 inch, the horizontal length of slot .437 inch, andthe width of the legs inch. Of course all dimensions are subject tovariation.

By this combination of features, the connector clamp of this inventionhas been found to be thoroughly dependable in permitting adequately firmclamping of the conductor, in spite of the fac that the main U-shapedbody 11 is sufficiently flexible so that the separable parts can besprung into place manually without undue effort. The ears 22automatically center the separable parts within the main body, thedownwardly and inwardly sloping central portions of the upper faces ofears 22 accomplishing the locking of the legs without the necessity ofprojecting more than slightly beyond the outer faces of the legs. Theswivelled clamp member 14 avoids any danger of cutting through theconductor as the clamp screw 12 is tightened down.

I claim:

1. A separable connector clamp including a cross piece having oppositelydisposed ears thereon and having a screw threaded therethrough, a clamppiece swivelled on the lower end of the screw and a U-shaped resilientmember having a base and two legs extending upwardly therefrom, saidlegs each having a slot near the upper end thereof for receiving an earof the cross piece; the resiliency of the U-shaped member permitting thecross piece to be sprung into place with its ears moving successivelyinto the slots, the upper faces of the ears extending higher outwardlyof the legs than at the inner faces of the legs to lock the legs on theears when an upward force is exerted on the cross piece by screwing thescrew downwardly to clamp a conductor within the clamp, the portions ofthe legs immediately above the slots lying substantially in verticalplanes through a distance greater than the thickness of the legs toresist the upward thrust of the cross piece thereon, each of the earshaving a relatively raised arcuate portion on its upper face positionedto engage the upper edge of the cooperating slot along an intermediateportion thereon to avoid placing the full load in shearing action on themetal adjacent the corner of the slot, and corners of the slots beingrounded.

2. A separable connector clamp including a cross piece having oppositelydisposed ears thereon and having a screw threaded therethrough and aU-shaped resilient member having a base and two legs extending upwardlytherefrom, said legs each having a slot near the upper end thereof forreceiving an ear of the cross piece; the resiliency of the U-shapedmember permitting the cross piece to be sprung into place with its earsmoving successively into the slots, the upper faces of the ears movingsuccessively into the slots,the upper faces of the ears extending higheroutwardly of the legs than at the inner faces of the legs to lock thelegs on the ears when air upward force is exerted on the cross piece byscrewing the screw downwardly to clamp a conductor within the clamp, theportions of the legs immediately above the slots lying substantially invertical planes through a distance greater than the thickness of thelegs to resist the upward thrust of the cross piece thereon, each of theears having a relatively raised arcuate portion on its upper facepositioned to engage the upper edge of the cooperating slot along anintermediate portion thereon to avoid placing the full load in shearingaction on the metal adjacent the corner of the slot.

3. A separable connector clamp including a cross piece having oppositelydisposed ears thereon and having a screw threaded therethrough and aU-shaped resilient member having a base and two legs extending upwardlytherefrom, said legs each having a slot near the upper end thereof forreceiving an ear of the cross piece; the resiliency of the U-shapedmember permitting the cross piece to be sprung into place with its earsmoving successively into the slots, the upper faces of the earsextending higher outwardly of the legs than at the inner faces of thelegs to lock the legs on the ears when an upward force is exerted on thecross piece by screwing the screw downwardly to clamp a conductor withinthe clamp, and each of the ears having a relatively raised arcuateportion on its upper face positioned to engage the upper edge of thecooperating slot along an intermediate portion thereon to avoid placingthe full load in shearing action on the metal adjacent the corner of theslot.

4-. A separable connector clamp including a cross piece havingoppositely disposed ears thereon and having a screw threadedtherethrough, a clamp piece swivelled on the lower end of the screw anda U-shaped resilient member having a base and two legs extendingupwardly therefrom, said legs each having a slot near the upper andthereof for receiving an ear of the cross piece; the dimension of theslot crosswise of the leg being only slightly greater than thecorresponding dimension of the ear; the resiliency of the U-shapedmember permitting the cross piece to be sprung into place with its earsmoving successively into the slots, the upper faces of the earsextending higher outwardly of the legs than at the inner edges of thelegs to lock the legs on the ears when an upward force is exerted on thecross piece by screwing the screw downwardly to clamp a conductor withinthe clamp, the portions of the legs immediately above the slots lyingsubstantially in vertical planes through a distance greater than thethickness of the legs to resist the upward thrust of the cross piecethereon, each of the ears having a relatively raised arcuate portion onits upper face positioned to engage the upper edge of the cooperatingslot along an intermediate portion thereon to avoid placing the fullload in shearing action on the metal adjacent the corner of the slot,and corners of the slots being rounded.

5. A separable connector clamp including a cross piece having oppositelydisposed ears thereon and having a screw threaded therethrough and aU-shaped resilient member having a base and two legs extending upwardlytherefrom, said legs each having a slot near the upper end thereof forreceiving an ear of the cross piece; the dimension of the slot crosswiseof the legs being only slightly greater than the corresponding dimensionof the ear; the resiliency of the U-shaped member permitting the crosspiece to be sprung into place with its ears moving successively into theslots, the upper faces of the ears extending higher outwardly of thelegs than at the inner edges of the legs to lock the legs on the earswhen an upward force is exerted on the cross piece by screwing the screwdownwardly to clamp a conductor within the clamp, the portions of thelegs immediately above the slots lying substantially in vertical planesthrough a distance greater than the thickness of the legs to resist theupward thrust of the cross piece thereon, each of the ears having arelatively raised arcuate portion on its upper face positioned to engagethe upper edge of the cooperating slot along an intermediate portionthereon to avoid placing the full load in shearing action on the metaladjacent the corner of the slot.

6. A separable connector clamp including a cross piece having oppositelydisposed ears thereon and having a screw threaded therethrough and aU-shaped resilient member having a base and two legs extending upwardlytherefrom, said legs each having a slot near the upper end thereof forreceiving an ear of the cross piece; the dimension of the slot crosswiseof the leg being only slightly greater than the corresponding dimensionof the ear; the resiliency of the U-shaped member permitting e25,877,443 t 5 the. cross piece to be sprung into place with its earsplacing the full load in shearing action on the metal adjamovingsuccessively into the slots, the upper faces of cent the corner of theslot. the ears extending higher outwardly of the legs than at the inneredges of the legs to lock the legs on the References Cited in the fileof this patent ears when an upward force is exerted on the cross piece 6by screwing the screw downwardly to clamp a con- UNITED STATES PATENTSductor within the clamp, and each of the ears having 2,107,859 FotshFeb. 8, 1938 a relatively raised arcuate portion on its upper face2,164,021 ROgOfi June 27, 1939 positioned to engage the upper edge ofthe cooperating 2,285,928 Jensen June 9, 1942 slot along an intermediateportion thereon to avoid 10 2,602,104 Hubbell et y 1, 1952

